Solar heating system and components thereof

ABSTRACT

A light weight, low cost, solar heating system is provided for use with homes and other buildings. Solar heating panels are mounted on a roof or other support and connected to the building&#39;&#39;s heating system. Water or other liquid medium is pumped to the elevated upper end of each unit and is allowed to drain down through each panel by gravity feed back into a storage tank where the heated water is circulated, on demand, through the building. Each heating panel is comprised of a rigid foam plastic frame having a back wall over which is disposed a reflective stratum. A sheet of plastic material having a black surface is bonded to the reflective stratum along spaced parallel lines to define a plurality of parallel channels extending lengthwise of the panel. Manifolds are provided at opposite ends of the panel to feed water into and drain water from the channels. Spaced layers of flexible, transparent plastic film are mounted to the frame across the front of the panel to pass radiant heat from the front to heat water in the channels and trap the heat absorbed by the panel.

United States Patent [1 1 Stout et a1.

[ Nov. 11, 1975 1 SOLAR HEATING SYSTEM AND COMPONENTS THEREOF [76]Inventors: Harry E. Stout; Brian Stout, both of 2 Brastow Ave.,Somerville, Mass. 02134 [22] Filed: July 17, 1974 [21] Appl. No.:489,150

Primary Eraminer-Kenneth W. Sprague Assistant E.\aminer-.1ames C. YeungAttorney, Agent, or Firm-Morse, Altman, Oates & Bello \IIIIIIIIIIII 5 7ABSTRACT A light weight, low cost, solar heating system is provided foruse with homes and other buildings. Solar heating panels are mounted ona roof or other support and connected to the buildings heating system.Water or other liquid medium is pumped to the elevated upper end of eachunit and is allowed to drain down through each panel by gravity feedback into a storage tank where the heated water is circulated, ondemand, through the building. Each heating panel is comprised of a rigidfoam plastic frame having a back wall over which is disposed areflective stratum. A sheet of plastic material having a black surfaceis bonded to the reflective stratum along spaced parallel lines todefine a plurality of parallel channels extending lengthwise of thepanel. Manifolds are provided at opposite ends of the panel to feedwater into and drain water from the channels. Spaced layers of flexible,transparent plastic film are mounted to the frame across the front ofthe panel to pass radiant heat from the front to heat water in thechannels and trap the heat absorbed by the panel.

3 Claims, 4 Drawing Figures US Patent Nov. 11, 1975 V .@W% n II IV 1 2 lI I I YI\IM I 1 h FIG 4 SOLAR HEATING BACKGROUND OF THE INVENTION 2 1.Field of the Invention I This invention relates generally to solarheating sys-' tems and more particularly isdirected towards a new andimproved, solar heating system employing simple, low cost light weightheating panels mountable to the roof of a building or the like.

2 Description of the Prior Art I With the increasing cost ofheatingfuels as well as the increase experiencedin the cost ofgenerating electricity, a'greater interest has developed in providingalternate sources of energy, particularly for hea-ting home's and otherbuildings. Solar heating systems are of partic ular interest since thesun provides asubstantially unlimited source of free energy and varioustypes of solar heating panels have been developed which utilize the sunsrays to heat water or the like-with the-water, in" turn, serving to heatthe building whichthe panels are associated. While solar heat systems ofthis type have functioned successfully; the high initial capital cost ofsystemspresently available'have preventedwidespread use of such systems.Also, for the most part, present solar heating systems have requiredspecially designed buildings involving relatively large, expensive andcom- SUMMARY OF THE INVENTION This invention featuresa solar, heatingsystem, comprising at least one solar panel fabricated with a lightweight frame of a rigid foam plastic material having a back wall andshallow marginal side walls'extending about the edges thereof. Areflective stratum is applied over the inner face of the back wall and alayer, of waterproof moldable plastic material is bonded to thereflective layer along spaced parallel lines to define a plurality ofparallel waterchannels between the plastic material and the reflectivebacking. Transparent plastic film is mounted across the frame openinginspaced parallel layers to trap heat generated by radiant energy from thesun passing through the film to heat the water in the channels. Theouter face of the plastic material forming the water channels is blackto enhance heat absorption. Manifolds are provided in the frame atopposite ends of channels by-which water is delivered at one end anddrained by gravity from the other end. A pumping system is provided forcirculating water and a storage tank is connected to the pumping systemto store water heated thereby.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in perspective of asolar heating-panel made according to the invention,

FIG. 2 is a fragmentary sectional view showing details of the panelconstruction.- I 1 I I FIG. 3 is a view somewhat similar-to FIG. 2showing further details of the panels, and,

SYSTEM AND COMPONENTS THEREOF Y FIG. 4 is a view in perspective,somewhat schematic, of a typical heating system employing panels of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to thedrawings, the reference character 10 generally indicates a solar heatingpanel made according to the invention and generally organized about arectangular frame 12 of a light weight, thermally insulating,inexpensive, material. Preferably the frame 12-is molded from styrofoamor other rigid, foam plastic material which is light in weight,inexpensive yet structually strong and having excellent thermalinsulation characteristics. The frame 12 is of a rectangularconfiguration formedwith integral, relatively short surrounding sidewalls 16. The dimensions of the frame 12 may be varied over a wide rangedepending upon particular applications. Typically, the panels are madeup of rather long sections on the order of perhaps 10 to 20 and in widthon the order of perhaps 3 or so. The dimensions are not critical butrather may be in a wide range. The wall 14 should be relatively thick toprovide good thermal insulation for the unit. In this regard, styrofoamis particularly effective as a thermal insulator in addition to itsadvantageous structual characteristics. The wall 14 may be /2 inch or soin thickness to provide both strength and proper insulating protectionfor the panel. The side wall 16 is relatively thick being on the orderof l-Vz to 2 inches both in height and width to reinforce the assembledpanels as well as to provide a clearance of possibly inch between theinner face of the wall 14 and the top of the wall 16 for reasons thatwill presently appear. The side walls 16 extend the full length of thepanel 10. End walls 18 and 20 are formed integral with the frame acrossthe full width of the panel and are of the same height as the side walls16. The end walls 18 and 20 are hollow to form a manifold chamber 22 forcommunciation with an inlet conduit 24 for the wall 18 and an outletconduit 26 for the wall 20,.

The walls 16, 18 and 20, in the preferred embodiment, are formed with agroove or recessed portion 28 extending about the upper outer edges ofthe walls to receive in nesting engagement stacked spacers 30(a), b),and (c), mounted one on top of the other Over the walls 16, 18 and 20 toprovide a predetermined spacing between multiple layers of transparentfilm 32 (a), (b), and (c). The function of the multiple layers oftransparent film 32 is to transmit radiant energy from the sun into thesolar heating panel 10 while insulating the panel against heat lossesthrough conduction and convection. In the preferred form of theinvention, the film layers 32 are spaced apart from one another by adistance of approximately A inch and, ideally, are two or three innumber. The spacers 30 are of matching size and configuration having alength and width corresponding to that of the panel 10 and formed aboutits inner lower corner with a recess 34 adapted to nest with the recess28 of the walls l6, l8 and 20 as well as with a recess 36 formed aboutthe upper outer edges of each of the spacers.

In fabricating the panels, the film layers 32 are stretched over theframe walls 16, 18 and 20 to a relatively taut and smooth surface. Inpractice, the innermost film layer 32 (a) is first placed in positionand securely bonded to the frame 14. One mode of assembly that has beenfoundto be particularly satisfactory is the use of heat'shrinkingtechniques involving thermoplastic films by which the films are shrunktightly onto the frame. Once the first layer 32 (a) is in position, thespacer 30 (a) is mounted over the walls 16, 18 and 20 and the secondtransparent film 32 (b) is applied. The same operation is repeated forthe next spacer (b) and the film layer 32 (c). A final optional spacer30 (0) maybe applied to form a protective member about the assembledstructure. Various types of films may be employed and should be-selectedaccording to their light transmission characteristics, durability,weathering characteristics, bonding qualities and the like. Varioustypesof polyethelyne, PVC, and other plastic films are suitable for thispurpose. The spacers 30, preferably of the same material as the frame14, are readily moldable from Styrofoam or other relatively rigid foamplastic material which is light in weight, structurally strong anddisplays excellent thermal insulating characteristics.

Within the solar panel there is disposed a reflective stratum 38 appliedto the upper face of the frame wall 14 and, for this purpose, aluminizedplastic, aluminum foil or other high reflective material, includingaluminized paint, may be employed. The reflective stratum 38 coverstheentire surface of the frame wall 14 and forms witha ply 40 a pluralityof spaced, parallel, water channels 42 disposed lengthwise across thewidth of the solar panel. The ply 40, in the preferred form of theinvention, is a moldable plastic material such as PVC or the like and isrelatively light in weight, waterproof and preferably adapted forthermal-forming techniques. The ply 40 is bonded along seams 44extending in parallel longitudinal relation to the stratum 38, as bestshown in FIG. 2. Typically, the bonding seams 44 are about /8 inch widewith the channels 42 being about 4 inches in width. As shown in FIG. 2,the ply 40 between the seams is raised somewhat from the face of thereflective stratum and typically an elevation of perhaps As inchprovides adequate flow of water. The function of the channels is to formwater into a relatively thin stream to facilitate heat transfer. In thisregard, the ply 40 should be a black body and is either of and entirelyblack material or has its surface coated as at 45 with a dull blacksubstance which will readily absorb the radiated heat from the sun. Thecombination of the black body absorption characteristics of the ply 40along with the reflective characteristics of the stratum 38 causes rapidheating of water flowing through the channels 42. On a typical sunnyday, temperatures on the order of 225 to 250F are obtainable within arelatively short period of time.

Each of the water channels 42 communicates with the manifold chambers 22in the upper and lower end walls 18 and 20 as by tubes 46 (FIG. 3)extending between the chambers 22 and into the ends of the waterchannel. A fillet 48 of sealing compound may be applied along the jointsto prevent leakage.'

In practice, each solar panel is mounted in a tilted position with theend wall 18 raised above the end wall 20 in the manner shown so thatwater fed into the upper manifold through the conduit 24 will flow bygravity down through the water channels 42 into the manifold of the endwall 20 and drain out through the conduit 26. Typically, the solarpanels are mounted on a pitched roof in the manner suggested in FIG. 4and a number of panels may be installed depending upon the particularrequirements of the building. Since each solar panelis relatively lightin weight and easily handled, it may be nailed onto an existing roofwithout the need of reinforcement or extra support. Nails can be readilydriven through the side walls of each panel or the unit may be cementedonto the roof. Preferably, an angle iron 50 is secured to the lower endof a pitched roof to provide support for the solar panel againstslipplng.

A system utilizing the solar panels is illustrated in FIG. 4 and, in theillustrated embodiment, four solar panels 10 (a), (b), (c) and (d) aremounted to a pitched roof of a building 52 with the panels extendingfrom the peak of the roof down to the eaves. Feed water is delivered bymeans of a pump 54 to a conduit 56 through branch lines 24 into themanifold 22 at the upper end of each solar heating panel. The relativelycool water flows by gravity down through the channels 42 in the heatingpanels becoming heated in the process and drains out through a drainline 58 down into a collecting tank 60, preferably within the building.The outlet conduits 26 may interconnect with the drain manifolds ofadjacent panels with the last connected to the line 58. The tank 60should be well insulated and, preferably, is provided with an auxiliaryheater 62 which may be electrical, oil fired, gas fired or the like. Theauxiliary heater is for use whenever heating requirements are not met bythe solar heating system as may occur after a number of cloudy days insuccession. The pump 54 is connected by a conduit 64 to the tank 60 andrecirculates the water through the'system. The heated water in the tank60 is removed by means of a pump 66 which circulates the heated waterthrough the heating system of the building. The heating system may bepreexisting and may include a number of radiators 68 connected byconduits 70 and 72 to the tank 60. For purposes of illustration, only asingle radiator and simple heating system are shown. Obviously, a morecomplex system may be utilized.

While water has been indicated as the heat transfer medium, obviously awide variety of liquids and liquefiable materials may be used in thesystem. For example, alcohol, salt water, liquid hydrocarbons, saltsolutions and various other heat transfer media may be employed in thesystem.

Having thus described the invention what we claim and desire to obtainby Letters Patent of the United States is:

1. A solar heating panel, comprising a. a frame of rigid foam plasticmaterial formed with a flat rear wall and integral marginal side and endwalls extending from one face and along the edges thereof,

b. a relective stratum disposed over said one face of said rear wall inflush face to face contact therewith,

c. a ply of waterproof plastic black body material bonded to saidstratum along spaced parallel lines extending lengthwise of said panelto form a plurality of elongated, parallel thin and relatively flatchannels between said end walls,

d. said end walls being hollow and communicating with said channels,

e. conduit means connected to said end walls for delivering a liquidmedium into one end wall, through said channels and from the other endwall, and

f. a plurality of strata of transparent plastic flexible sheet materialmounted to said side and end walls 3. A solar heating panel according toclaim 1 wherein said side and end walls are formed with a marginalrecess along their upper outer edges and each of said spacer members isformed with a cooperating recess along its lower inner edges for matingengagement with the recess of said side and end walls and another recessalong its upper outer edges for mating engagement with a similar spacermember nested thereon.

l l l= l

1. A solar heating panel, comprising a. a frame of rigid foam plasticmaterial formed with a flat rear wall and integral marginal side and endwalls extending from one face and along the edges thereof, b. arelective stratum disposed over said one face of said rear wall in flushface to face contact therewith, c. a ply of waterproof plastic blackbody material bonded to said stratum along spaced parallel linesextending lengthwise of said panel to form a plurality of elongated,parallel thin and relatively flat channels between said end walls, d.said end walls being hollow and communicating with said channels, e.conduit means connected to said end walls for delivering a liquid mediuminto one end wall, through said channels and from the other end wall,and f. a plurality of strata of transparent plastic flexible sheetmaterial mounted to said side and end walls in spaced parallel relationto one another and to said rear wall, and, g. spacer members of rigidfoam plastic material mounted along said side and end walls between eachstratum of sheet material.
 2. A solar heating panel according to claim 1wherein said sheet material is heat shrinkable and each stratum ofmaterial is heat shrunk over said panel and said spacer members toconnect said panel, spacer members and strata into a sealed unit.
 3. Asolar heating panel according to claim 1 wherein said side and end wallsare formed with a marginal recess along their upper outer edges and eachof said spacer members is formed with a cooperating Recess along itslower inner edges for mating engagement with the recess of said side andend walls and another recess along its upper outer edges for matingengagement with a similar spacer member nested thereon.